The invention relates to a system for eliminating noise produced while recording an image on a recording medium and, more particularly, to a noise eliminating system utilized in apparatus for scanning an original document image to convert it into binary electric signals corresponding to plural parallel scan lines and for recording the image on a sheet of paper or for displaying it on a CRT.
It has been proposed previously to scan an original document image in order to convert it into a series of electric image signals and to re-order the image signals so as to provide a converted or coded image different from the original document image to reduce the amount of stored data for easy transport and storage. In reproducing such a converted image, the converted image should be converted into electric signals in the same phase relationship as at the time of scanning the original document image in order to properly reproduce a converted image corresponding to the original document image. A poorly coordinated phase relationship will cause noise in the reproduced image and degrade the image quality. As the amount of phase distortion increases, such noise becomes correspondingly greater until eventually the converted image cannot be reproduced. In order to provide a good phase relationship, it has been proposed to record reference marks on the converted image simultaneously with the conversion of the original document image. However, this fails to fully eliminate the noise problem. Accordingly, there is a need for a noise elimination system which is capable of attaining a higher quality reproduced image.